Railroad giant (CSX - Get Report) late Tuesday said it was calling a special shareholder meeting to seek guidance from investors about whether to support a series of proposals issued by an activist investor who is seeking to replace the company's CEO and obtain six director seats on a newly formulated fourteen-person board.

The activist investor, Mantle Ridge LP, a newly formed activist fund led by Paul Hilal, recently launched a campaign that is seeking to install veteran railroad executive Hunter Harrison as CEO at CSX. Harrison recently stepped down from his position as CEO of Canadian Pacific Railway  (CP) to join Mantle Ridge.

The two sides have been negotiating, but a key dispute appears to involve Harrison's compensation and how many seats on the board Mantle Ridge would receive.

Hilal is seeking to designate six of fourteen directors on a reconstituted fourteen person board, including a seat for himself and one for Harrison. In addition, the activists want three incumbent directors to resign at the 2017 annual meeting and one more to step down in 2018.

CSX said in a statement that the Mantle Ridge proposal hasn't been approved by the railroad, which had made a counteroffer that involved hiring Harrison as CEO, who would replace the current chief executive, Michael Ward. In addition, CSX offered to install Harrison, Hilal and three other "mutually agreed" upon directors to the board while four incumbent nominees would resign over the next three years.

So far no date has been set for the meeting, but shareholders who hold shares as of March 16 will be permitted to vote at it.

It's very possible that Mantle Ridge will pull the trigger on a change-of-control proxy contest if shareholders back their plan at the special meeting and the company doesn't give in to their demands. An ex-Pershing Square partner, Hilal largely engineered a spectacularly successful insurgency in 2012 at Canadian Pacific that installed Harrison as CEO, orchestrating a turnaround there that led Canadian Pacific's Toronto-based shares to climb nearly 190% in his tenure. 

If Harrison becomes the next CEO of CSX, as many expect will happen, look for operational changes, stock buybacks and a blockbuster merger attempt in the years to come.